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Bioenergy is a type of renewable energy that is derived from plants and animal waste.[1] The biomass that is used as input materials consists of recently living (but now dead) organisms, mainly plants.[2] Thus, fossil fuels are not regarded as biomass under this definition. Types of biomass commonly used for bioenergy include wood, food crops such as corn, energy crops and waste from forests, yards, or farms.[3]
Bioenergy can help with climate change mitigation but in some cases the required biomass production can increase greenhouse gas emissions or lead to local biodiversity loss. The environmental impacts of biomass production can be problematic, depending on how the biomass is produced and harvested.
The IEA's Net Zero by 2050 scenario calls for traditional bioenergy to be phased out by 2030, with modern bioenergy's share increasing from 6.6% in 2020 to 13.1% in 2030 and 18.7% in 2050.[4] Bioenergy has a significant climate change mitigation potential if implemented correctly.[5]: 637 Most of the recommended pathways to limit global warming include substantial contributions from bioenergy in 2050 (average at 200 EJ).[6]: B 7.4
Definition and terminology
editThe IPCC Sixth Assessment Report defines bioenergy as "energy derived from any form of biomass or its metabolic by-products".[7]: 1795 It goes on to define biomass in this context as "organic material excluding the material that is fossilised or embedded in geological formations".[7]: 1795 This means that coal or other fossil fuels is not a form of biomass in this context.
The term traditional biomass for bioenergy means "the combustion of wood, charcoal, agricultural residues and/or animal dung for cooking or heating in open fires or in inefficient stoves as is common in low-income countries".[7]: 1796
Since biomass can also be used as a fuel directly (e.g. wood logs), the terms biomass and biofuel have sometimes been used interchangeably. However, the term biomass usually denotes the biological raw material the fuel is made of. The terms biofuel or biogas are generally reserved for liquid or gaseous fuels respectively.[8]
Input materials
editWood and wood residues is the largest biomass energy source today. Wood can be used as a fuel directly or processed into pellet fuel or other forms of fuels. Other plants can also be used as fuel, for instance maize, switchgrass, miscanthus and bamboo.[9] The main waste feedstocks are wood waste, agricultural waste, municipal solid waste, and manufacturing waste. Upgrading raw biomass to higher grade fuels can be achieved by different methods, broadly classified as thermal, chemical, or biochemical:
Thermal conversion processes use heat as the dominant mechanism to upgrade biomass into a better and more practical fuel. The basic alternatives are torrefaction, pyrolysis, and gasification, these are separated mainly by the extent to which the chemical reactions involved are allowed to proceed (mainly controlled by the availability of oxygen and conversion temperature).[10]
Many chemical conversions are based on established coal-based processes, such as the Fischer-Tropsch synthesis.[11] Like coal, biomass can be converted into multiple commodity chemicals.[12]
Biochemical processes have developed in nature to break down the molecules of which biomass is composed, and many of these can be harnessed. In most cases, microorganisms are used to perform the conversion. The processes are called anaerobic digestion, fermentation, and composting.[13]
Applications
editBiomass for heating
editBiofuel for transportation
editBased on the source of biomass, biofuels are classified broadly into two major categories, depending if food crops are used or not:[14]
First-generation (or "conventional") biofuels are made from food sources grown on arable lands, such as sugarcane and maize. Sugars present in this biomass are fermented to produce bioethanol, an alcohol fuel which serves as an additive to gasoline, or in a fuel cell to produce electricity. Bioethanol is made by fermentation, mostly from carbohydrates produced in sugar or starch crops such as corn, sugarcane, or sweet sorghum. Bioethanol is widely used in the United States and in Brazil. Biodiesel is produced from the oils in for instance rapeseed or sugar beets and is the most common biofuel in Europe.[citation needed]
Second-generation biofuels (also called "advanced biofuels") utilize non-food-based biomass sources such as perennial energy crops and agricultural residues/waste. The feedstock used to make the fuels either grow on arable land but are byproducts of the main crop, or they are grown on marginal land. Waste from industry, agriculture, forestry and households can also be used for second-generation biofuels, using e.g. anaerobic digestion to produce biogas, gasification to produce syngas or by direct combustion. Cellulosic biomass, derived from non-food sources, such as trees and grasses, is being developed as a feedstock for ethanol production, and biodiesel can be produced from left-over food products like vegetable oils and animal fats.[citation needed]
Production of liquid fuels
editComparison with other renewable energy types
editLand requirement
editThe surface power production densities of a crop will determine how much land is required for production. The average lifecycle surface power densities for biomass, wind, hydro and solar power production are 0.30 W/m2, 1 W/m2, 3 W/m2 and 5 W/m2, respectively (power in the form of heat for biomass, and electricity for wind, hydro and solar).[15] Lifecycle surface power density includes land used by all supporting infrastructure, manufacturing, mining/harvesting and decommissioning.
Another estimate puts the values at 0.08 W/m2 for biomass, 0.14 W/m2 for hydro, 1.84 W/m2 for wind, and 6.63 W/m2 for solar (median values, with none of the renewable sources exceeding 10 W/m2).[16]
Related technologies
editBioenergy with carbon capture and storage (BECCS)
editCarbon capture and storage technology can be used to capture emissions from bioenergy power plants. This process is known as bioenergy with carbon capture and storage (BECCS) and can result in net carbon dioxide removal from the atmosphere. However, BECCS can also result in net positive emissions depending on how the biomass material is grown, harvested, and transported. Deployment of BECCS at scales described in some climate change mitigation pathways would require converting large amounts of cropland.[17]
Bioenergy with carbon capture and storage (BECCS) is the process of extracting bioenergy from biomass and capturing and storing as much as possible of the resulting CO2, thereby moving it from the biogenic carbon pool to the geological carbon pool. BECCS can theoretically be a "negative emissions technology" (NET),[19] although its deployment at the scale considered by many governments and industries can "also pose major economic, technological, and social feasibility challenges; threaten food security and human rights; and risk overstepping multiple planetary boundaries, with potentially irreversible consequences".[20] The carbon in the biomass comes from the greenhouse gas carbon dioxide (CO2) which is extracted from the atmosphere by the biomass when it grows. Energy ("bioenergy") is extracted in useful forms (electricity, heat, biofuels, etc.) as the biomass is utilized through combustion, fermentation, pyrolysis or other conversion methods.
Some of the carbon in the biomass is converted to CO2 or biochar which can then be stored by geologic sequestration or land application, respectively, enabling carbon dioxide removal (CDR).[19]
The potential range of negative emissions from BECCS was estimated to be zero to 22 gigatonnes per year.[21] As of 2019[update], five facilities around the world were actively using BECCS technologies and were capturing approximately 1.5 million tonnes per year of CO2.[22] Wide deployment of BECCS is constrained by cost and availability of biomass.[23][24]: 10Climate and sustainability aspects
editThe climate impact of bioenergy varies considerably depending on where biomass feedstocks come from and how they are grown.[26] For example, burning wood for energy releases carbon dioxide; those emissions can be significantly offset if the trees that were harvested are replaced by new trees in a well-managed forest, as the new trees will absorb carbon dioxide from the air as they grow.[27] However, the establishment and cultivation of bioenergy crops can displace natural ecosystems, degrade soils, and consume water resources and synthetic fertilisers.[28][29]
Approximately one-third of all wood used for traditional heating and cooking in tropical areas is harvested unsustainably.[30] Bioenergy feedstocks typically require significant amounts of energy to harvest, dry, and transport; the energy usage for these processes may emit greenhouse gases. In some cases, the impacts of land-use change, cultivation, and processing can result in higher overall carbon emissions for bioenergy compared to using fossil fuels.[29][31]
Use of farmland for growing biomass can result in less land being available for growing food. In the United States, around 10% of motor gasoline has been replaced by corn-based ethanol, which requires a significant proportion of the harvest.[32][33] In Malaysia and Indonesia, clearing forests to produce palm oil for biodiesel has led to serious social and environmental effects, as these forests are critical carbon sinks and habitats for diverse species.[34][35] Since photosynthesis captures only a small fraction of the energy in sunlight, producing a given amount of bioenergy requires a large amount of land compared to other renewable energy sources.[36]Environmental impacts
editBioenergy can either mitigate (i.e. reduce) or increase greenhouse gas emissions. There is also agreement that local environmental impacts can be problematic.[citation needed] For example, increased biomass demand can create significant social and environmental pressure in the locations where the biomass is produced.[37] The impact is primarily related to the low surface power density of biomass. The low surface power density has the effect that much larger land areas are needed in order to produce the same amount of energy, compared to for instance fossil fuels.
Long-distance transport of biomass have been criticised as wasteful and unsustainable,[38] and there have been protests against forest biomass export in Sweden[39] and Canada.[40]
Scale and future trends
editIn 2020 bioenergy produced 58 EJ (exajoules) of energy, compared to 172 EJ from crude oil, 157 EJ from coal, 138 EJ from natural gas, 29 EJ from nuclear, 16 EJ from hydro and 15 EJ from wind, solar and geothermal combined.[41] Most of the global bioenergy is produced from forest resources.[42]: 3 [43]: 1
Generally, bioenergy expansion fell by 50% in 2020. China and Europe are the only two regions that reported significant expansion in 2020, adding 2 GW and 1.2 GW of bioenergy capacity, respectively.[44]
Almost all available sawmill residue is already being utilized for pellet production, so there is no room for expansion. For the bioenergy sector to significantly expand in the future, more of the harvested pulpwood must go to pellet mills. However, the harvest of pulpwood (tree thinnings) removes the possibility for these trees to grow old and therefore maximize their carbon holding capacity.[45]: 19 Compared to pulpwood, sawmill residues have lower net emissions: "Some types of biomass feedstock can be carbon-neutral, at least over a period of a few years, including in particular sawmill residues. These are wastes from other forest operations that imply no additional harvesting, and if otherwise burnt as waste or left to rot would release carbon to the atmosphere in any case."[45]: 68
By country
editSee also
editReferences
edit- ^ "Renewable Energy Sources and Climate Change Mitigation. Special Report of the Intergovernmental Panel on Climate Change" (PDF). IPCC. 2012. Archived (PDF) from the original on 2019-04-12. Retrieved 9 March 2024.
- ^ "Bioenergy Basics". Energy.gov. Retrieved 2023-05-25.
- ^ "Biomass – Energy Explained, Your Guide To Understanding Energy". U.S. Energy Information Administration. June 21, 2018.
- ^ "What does net-zero emissions by 2050 mean for bioenergy and land use? – Analysis". IEA. Retrieved 2023-01-19.
- ^ Smith, P., J. Nkem, K. Calvin, D. Campbell, F. Cherubini, G. Grassi, V. Korotkov, A.L. Hoang, S. Lwasa, P. McElwee, E. Nkonya, N. Saigusa, J.-F. Soussana, M.A. Taboada, 2019: Chapter 6: Interlinkages Between Desertification, Land Degradation, Food Security and Greenhouse Gas Fluxes: Synergies, Trade-offs and Integrated Response Options. In: Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems [P.R. Shukla, J. Skea, E. Calvo Buendia, V. Masson-Delmotte, H.- O. Portner, D. C. Roberts, P. Zhai, R. Slade, S. Connors, R. van Diemen, M. Ferrat, E. Haughey, S. Luz, S. Neogi, M. Pathak, J. Petzold, J. Portugal Pereira, P. Vyas, E. Huntley, K. Kissick, M. Belkacemi, J. Malley, (eds.)]. In press.
- ^ IPCC, 2019: Summary for Policymakers. In: Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems [P.R. Shukla, J. Skea, E. Calvo Buendia, V. Masson-Delmotte, H.- O. Pörtner, D. C. Roberts, P. Zhai, R. Slade, S. Connors, R. van Diemen, M. Ferrat, E. Haughey, S. Luz, S. Neogi, M. Pathak, J. Petzold, J. Portugal Pereira, P. Vyas, E. Huntley, K. Kissick, M. Belkacemi, J. Malley, (eds.)]. https://doi.org/10.1017/9781009157988.001
- ^ a b c IPCC, 2022: Annex I: Glossary [van Diemen, R., J.B.R. Matthews, V. Möller, J.S. Fuglestvedt, V. Masson-Delmotte, C. Méndez, A. Reisinger, S. Semenov (eds)]. In IPCC, 2022: Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [P.R. Shukla, J. Skea, R. Slade, A. Al Khourdajie, R. van Diemen, D. McCollum, M. Pathak, S. Some, P. Vyas, R. Fradera, M. Belkacemi, A. Hasija, G. Lisboa, S. Luz, J. Malley, (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA. doi: 10.1017/9781009157926.020
- ^ "Biofuels explained - U.S. Energy Information Administration (EIA)". www.eia.gov. Retrieved 2023-01-23.
- ^ Darby, Thomas. "What Is Biomass Renewable Energy". Real World Energy. Archived from the original on 2014-06-08. Retrieved 12 June 2014.
- ^ Akhtar, Krepl & Ivanova 2018.
- ^ Liu et al. 2011.
- ^ Conversion technologies Archived 2009-10-26 at the Wayback Machine. Biomassenergycentre.org.uk. Retrieved on 2012-02-28.
- ^ "Biochemical Conversion of Biomass". BioEnergy Consult. 2014-05-29. Retrieved 2016-10-18.
- ^ Pishvaee, Mohseni & Bairamzadeh 2021, pp. 1–20.
- ^ Smil, Vaclav (2015). Power density : a key to understanding energy sources and uses. Cambridge, Massachusetts. pp. 26–27, 211, box 7.1. ISBN 978-0-262-32692-6. OCLC 927400712.
{{cite book}}
: CS1 maint: location missing publisher (link) - ^ Van Zalk, John; Behrens, Paul (2018-12-01). "The spatial extent of renewable and non-renewable power generation: A review and meta-analysis of power densities and their application in the U.S." Energy Policy. 123: 86. Bibcode:2018EnPol.123...83V. doi:10.1016/j.enpol.2018.08.023. hdl:1887/64883. ISSN 0301-4215.
- ^ National Academies of Sciences, Engineering, and Medicine 2019, p. 3.
- ^ Sanchez, Daniel L.; Kammen, Daniel M. (2015-09-24). "Removing Harmful Greenhouse Gases from the Air Using Energy from Plants". Frontiers for Young Minds. 3. doi:10.3389/frym.2015.00014. ISSN 2296-6846.
- ^ a b National Academies of Sciences, Engineering (2018-10-24). Negative Emissions Technologies and Reliable Sequestration: A Research Agenda. doi:10.17226/25259. ISBN 978-0-309-48452-7. PMID 31120708. S2CID 134196575. Archived from the original on 2020-05-25. Retrieved 2020-02-22.
- ^ Deprez, Alexandra; Leadley, Paul; Dooley, Kate; Williamson, Phil; Cramer, Wolfgang; Gattuso, Jean-Pierre; Rankovic, Aleksandar; Carlson, Eliot L.; Creutzig, Felix (2024-02-02). "Sustainability limits needed for CO 2 removal". Science. 383 (6682): 484–486. doi:10.1126/science.adj6171. ISSN 0036-8075. PMID 38301011. S2CID 267365599.
- ^ Smith, Pete; Porter, John R. (July 2018). "Bioenergy in the IPCC Assessments". GCB Bioenergy. 10 (7): 428–431. Bibcode:2018GCBBi..10..428S. doi:10.1111/gcbb.12514. hdl:2164/10480.
- ^ "BECCS 2019 perspective" (PDF). Archived (PDF) from the original on 2020-03-31. Retrieved 2019-06-11.
- ^ Rhodes, James S.; Keith, David W. (2008). "Biomass with capture: Negative emissions within social and environmental constraints: An editorial comment". Climatic Change. 87 (3–4): 321–8. Bibcode:2008ClCh...87..321R. doi:10.1007/s10584-007-9387-4.
- ^ Fajardy, Mathilde; Köberle, Alexandre; Mac Dowell, Niall; Fantuzzi, Andrea (2019). "BECCS deployment: a reality check" (PDF). Grantham Institute Imperial College London.
- ^ Cowie, Annette L.; Berndes, Göran; Bentsen, Niclas Scott; Brandão, Miguel; Cherubini, Francesco; Egnell, Gustaf; George, Brendan; Gustavsson, Leif; Hanewinkel, Marc; Harris, Zoe M.; Johnsson, Filip; Junginger, Martin; Kline, Keith L.; Koponen, Kati; Koppejan, Jaap (2021). "Applying a science-based systems perspective to dispel misconceptions about climate effects of forest bioenergy". GCB Bioenergy. 13 (8): 1210–1231. Bibcode:2021GCBBi..13.1210C. doi:10.1111/gcbb.12844. hdl:10044/1/89123. ISSN 1757-1693. S2CID 235792241.
- ^ Correa, Diego F.; Beyer, Hawthorne L.; Fargione, Joseph E.; Hill, Jason D.; et al. (2019). "Towards the implementation of sustainable biofuel production systems". Renewable and Sustainable Energy Reviews. 107: 250–263. doi:10.1016/j.rser.2019.03.005. ISSN 1364-0321. S2CID 117472901. Archived from the original on 17 July 2021. Retrieved 7 February 2021.
- ^ Daley, Jason (24 April 2018). "The EPA Declared That Burning Wood Is Carbon Neutral. It's Actually a Lot More Complicated". Smithsonian Magazine. Archived from the original on 30 June 2021. Retrieved 14 September 2021.
- ^ Tester 2012, p. 512.
- ^ a b Smil 2017a, p. 162.
- ^ World Health Organization 2016, p. 73.
- ^ IPCC 2014, p. 616.
- ^ "Biofuels explained: Ethanol". US Energy Information Administration. 18 June 2020. Archived from the original on 14 May 2021. Retrieved 16 May 2021.
- ^ Foley, Jonathan (5 March 2013). "It's Time to Rethink America's Corn System". Scientific American. Archived from the original on 3 January 2020. Retrieved 16 May 2021.
- ^ Ayompe, Lacour M.; Schaafsma, M.; Egoh, Benis N. (1 January 2021). "Towards sustainable palm oil production: The positive and negative impacts on ecosystem services and human wellbeing". Journal of Cleaner Production. 278: 123914. doi:10.1016/j.jclepro.2020.123914. ISSN 0959-6526. S2CID 224853908.
- ^ Lustgarten, Abrahm (20 November 2018). "Palm Oil Was Supposed to Help Save the Planet. Instead It Unleashed a Catastrophe". The New York Times. ISSN 0362-4331. Archived from the original on 17 May 2019. Retrieved 15 May 2019.
- ^ Smil 2017a, p. 161.
- ^ Climate Central 2015.
- ^ IFL Science 2016.
- ^ Forest Defenders Alliance 2021.
- ^ STAND.earth 2021.
- ^ "Energy Statistics Data Browser – Data Tools". IEA. Retrieved 2022-12-27.
- ^ WBA (2019) GLOBAL BIOENERGY STATISTICS 2019 World Bioenergy Association
- ^ European Commission, Joint Research Centre (JRC), Brief on biomass for energy in the European Union, Publications Office, 2019
- ^ "World Adds Record New Renewable Energy Capacity in 2020". /newsroom/pressreleases/2021/Apr/World-Adds-Record-New-Renewable-Energy-Capacity-in-2020. 5 April 2021. Retrieved 2021-11-22.
- ^ a b Brack, D. (2017) Woody Biomass for Power and Heat Impacts on the Global Climate. Research Paper - Environment, Energy and Resources Department.
Sources
edit- Pishvaee, Mir Saman; Mohseni, Shayan; Bairamzadeh, Samira (2021). "An overview of biomass feedstocks for biofuel production". Biomass to Biofuel Supply Chain Design and Planning Under Uncertainty. Elsevier. doi:10.1016/b978-0-12-820640-9.00001-5. ISBN 978-0-12-820640-9. S2CID 230567249.
- Akhtar, Ali; Krepl, Vladimir; Ivanova, Tatiana (2018-07-05). "A Combined Overview of Combustion, Pyrolysis, and Gasification of Biomass". Energy & Fuels. 32 (7). American Chemical Society (ACS): 7294–7318. doi:10.1021/acs.energyfuels.8b01678. ISSN 0887-0624. S2CID 105089787.
- Liu, Guangjian; Larson, Eric D.; Williams, Robert H.; Kreutz, Thomas G.; Guo, Xiangbo (2011-01-20). "Making Fischer−Tropsch Fuels and Electricity from Coal and Biomass: Performance and Cost Analysis". Energy & Fuels. 25 (1). American Chemical Society (ACS): 415–437. doi:10.1021/ef101184e. ISSN 0887-0624.
- National Academies of Sciences, Engineering, and Medicine (2019). Negative Emissions Technologies and Reliable Sequestration: A Research Agenda. doi:10.17226/25259. ISBN 978-0-309-48452-7. PMID 31120708. S2CID 134196575. Archived from the original on 25 May 2020.
- Climate Central (2015-10-23). "Pulp Fiction, The Series". Retrieved 2022-02-12.
- IFL Science (2016-03-14). "British Power Stations Are Burning Wood From US Forests – To Meet Renewables Target".
- Forest Defenders Alliance (2021). "Standing up for forests and against the Swedish forestry model: A letter to EC policymakers".
- STAND.earth (2021-03-23). "Risk Map: Primary forest and threatened caribou habitat overlap with preliminary estimated wood pellet haul zones for Pinnacle/Drax in British Columbia".
- Tester, Jefferson (2012). Sustainable Energy: Choosing Among Options. MIT Press. ISBN 978-0-262-01747-3. OCLC 892554374.
- Smil, Vaclav (2017a). Energy Transitions: Global and National Perspectives. Praeger Publishing. ISBN 978-1-4408-5324-1. OCLC 955778608.
- IPCC (2014). Edenhofer, O.; Pichs-Madruga, R.; Sokona, Y.; Farahani, E.; et al. (eds.). Climate Change 2014: Mitigation of Climate Change: Working Group III contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press. ISBN 978-1-107-05821-7. OCLC 892580682. Archived from the original on 26 January 2017.
- World Health Organization (2016). Burning Opportunity: Clean Household Energy for Health, Sustainable Development, and Wellbeing of Women and Children (PDF). ISBN 978-92-4-156523-3. Archived (PDF) from the original on 13 June 2021.